1. Field of the Invention
The present invention relates to a thin film magnetic head and, more particularly, to a thin film magnetic head suitable for use in a magnetic disk apparatus.
Particularly, the present invention has a feature in a magnetic core.
2. Description of the Prior Art
Hitherto, Permalloy, which is a binary alloy of nickel of about 80 weight % and iron of about 20 weight %, has been used as a magnetic core material for thin film magnetic heads. This material has an almost null magneto-striction coefficient and a high magnetic permeability in the high frequency region. Therefore, the thin film magnetic head using this magnetic core material has excellent readout performance.
However, the saturation magnetic flux density of Permalloy is low, i.e. about one tesla. Thus, the writing performance of the thin film magnetic head using the magnetic core of Permalloy is not high. Practically speaking, in magnetic disk apparatuses, there is a tendency that a material having a high coercive force is used as a material of the recording medium from the viewpoint of realization of a high recording density. The thin film magnetic head having a magnetic core of Permalloy has degraded writing performance to the recording medium of a high coercive force.